There are other & cheaper line level devices out there than the SVS Unit. I just assumed that since SVS had been mainly focused on subs that they designed it correctly. I only use it depending on the preamp I'm using but I feel like it works well.
When using a proper solid state amp I feel like I lose nothing..maybe having to add a tick more gain to the sub sometimes. The device does reduce the voltage around negative 30dBV. Adding no noise, distortion, or compromising the amp in any way. With certain tube amps I've perceived some differences in the subs performance.
It can handle high voltages like 500 watts RMS & double that for peaks. It has binding posts for inputs..I use spades at the amp and banana plugs to the SVS device. It basically just safely converts high voltage amp output to low level rca outputs. It's a passive device which I like.. nothing extra to plug in or ground. No matter which amp I've used I've never heard any dc thump or other noises when turning the amp off while the sub is on. Which is how it should be.
It's a cool little device to always have at your disposal. Though if you buy or have quality sub/subs with high level inputs already available there is no need for this device. I primarily have been using SVS subs the last 5 years or so. I don't have speakers that demand ultimate speed or sensitivity from a sub. And the SVS DSP phone app was a game changer for me at the time. The room compensation feature & just the 3 PEQ tabs of the original Pro models made integration so much easier & better. Their newer models offer 5 PEQ tabs now I believe. My older Pro models might not be the best in overall performance but for me the PEQ/DSP options make up for it. Though I do see more sub manufacturers adding some type of legit DSP to their subs.